1. Field of the Invention
The present invention relates to a device and a method for information processing, and particularly to a device and a method for information processing and a program that can reduce the load of coding or decoding data.
2. Description of the Related Art
An archive system or an image database in the past performs operations of storing and retaining a non-compressed image referred to as a master image, compressing the non-compressed image as required, and distributing a file as a result of the compression via a network or saving the file to recording media, for example.
In film making, a picture is first taken on a 35-mm or 60-mm film, and converted to digital data using a device referred to as a film scan converter. This digitized film source becomes a master image.
Also in a case of medical use, though an image of an X-ray photograph can directly become non-compressed data in some cases, digital data obtained by a film scan as in the above becomes a master image in a case of film.
In addition, many of recent single-lens reflex digital cameras can store RAW data or RGB data obtained from a CCD (Charge Coupled Device) or CMOS (Complementary Metal Oxide Semiconductor) image sensor on a memory card with the RAW data or RGB data remaining in a non-compressed state.
As described above, non-compressed master images are important because of the integrity of data as images, but have a disadvantage of massive data size. Thus, when a master image is to be transferred via a network or when many images are to be recorded on a memory card, some compression (encoding) is unavoidable.
In addition, because the capacity of a hard disk for recording such master images is limited, means is adopted which losslessly compresses master images and stores the losslessly compressed file on a hard disk. At this time, it is convenient to save the master images to a less expensive recording medium such as a tape or the like.
As technology of lossless compression, Zip, LZ77 compression and the like generally used for file compression are well known, but have a problem of being unsuitable for image compression (poor compression ratio) An international standard of JPEG (Joint Photographic Experts Group) has JPEG-LS standardized as a lossless compression, but JPEG-LS is not spread at all in terms of practical use.
Standards for lossless compression further include JPEG2000 (see Japanese Patent No. 3906630, referred to as Patent Document 1 hereinafter, for example). JPEG2000 provides two compression options, that is, lossless compression and lossy compression, and has another excellent advantage of scalability (resolution, image quality, components and the like) and the like. This JPEG2000 is used for the digital cinema, for example, as a lossy compression. A DCI standard (Digital Cinema Initiatives) provides that JPEG2000 Part-1 be used as compression and decompression techniques.
JPEG2000 is also used as lossless compression. For example, JPEG2000 is used for compression when a non-compressed master image is stored temporarily. In addition, utilizing scalability as a feature of JPEG2000, JPEG2000 is also used in a case where a compressed file is first generated by performing lossless compression, and is converted into an irreversible file of the DCI standard or the like as required.
Patent Document 1 describes an image coding device that has both a fixed-point type wavelet transform part and an integer type wavelet transform part, which can perform both a lossy transform and a lossless transform, and which is capable of increasing a degree of freedom of selection of image quality and compression ratio.